1. field of the Invention
The present invention relates to presses comprising a pair of rolls arranged one to another to provide an adjustable nip therebetween. Accordingly, the invention relates to roller-type presses. The present invention more particularly relates to improvements in invention more particularly relates to improvements in such presses and methods based on use of such presses.
The present invention also relates to paper-making, and more particularly to a hot press for squeezing moisture from a continuous ribbon or web, such as paper and carrying felt. The press may also be used, for example, as a smoothing press, sizing press, reverse press and breaker press.
2. Description of the Prior Art
Most rolls in papermachine presses are supported at both ends by journals, normally solid, that have a much smaller diameter than the roll diameter. Sometimes the relatively small diameter journals are hollow, to accommodate heating means such as steam, to provide hot pressing. Both solid and hollow journals rotate with the roll. Also, the roll body acts as a rotary beam, for nip pressure.
Other rolls in papermachine presses are supported at both ends, likewise by hollow journals that rotate with the roll, but of large enough bore to admit a suction box into the roll. Again, the roll body acts as a rotary beam, for nip pressure.
Another type of known press roll comprises an outer rolling shell, and a separate fixed beam inside, with roller or equivalent bearings between shell and beam at the roll ends. Straight seals extending the full beam length, and attached to opposite sides of the beam, all combine with end seals to divide an annular space between shell and beam into two fixed chambers of "C" cross-section. A controlled hydraulic pressure is applied in one of the "C" chambers to deflect shell from beam a controlled amount, thereby to offset deflection from nip loading. The construction is known as a "swimming roll".
A further type of known press roll comprises an outer rolling shell and an inner fixed beam somewhat like a "swimming roll", except that the space for hydraulic pressure is occupied instead by lubricated stationary pads, adjustable to deflect shell from beam a controlled amount and likewise to offset deflection from nip loading.
A further type of known press roll utilizes an inflatable interior for bulging a roll body, slightly to a barrel shape, thereby to offset deflection from nip loading.